THE APPLICATION OF SELECTIVE ROE EXPERIMENTS TO STUDY SOLUTION STRUCTURES OF CYCLOMALTOOLIGOSACCHARIDE DERIVATIVES AND COMPLEXES

Selective one-dimensional ROE experiments were applied to study the ho st-guest interactions of cyclomaltohexaose with p-nitrophenol and the solution structure of -(4-methylamino-3-nitrobenzyl)-cyclomaltoheptaos e. The line selective excitation of the aromatic signals of p-nitrophe nol gave intense ROE enhancements on the cyclomaltohexaose multiplets (H3 and H5), indicating deep complexation inside the cavity. The resul ts on A-(4-methylamino-3-nitrobenzyl)-cyclomaltpheptaose showed that t he aromatic moiety covers the wider base of the cyclomaltoheptaose con e. The rotational correlation time for this compound was calculated to be 2.9x10(-10) s using carbon-13 spin-lattice relaxation data. Quanti tative analysis of the measured enhancements was performed and proton- proton distances were obtained between the aromatic and cyclomalthepto ase protons as well as interglycosidic distances inside the cyclomalth eptaose moiety. (C) 1998 Elsevier Science Ltd. All rights reserved.